A special team of federal inspectors was called to the San Onofre Nuclear Generating Station just south of San Clemente after seven tubes that carry radioactive water failed pressure tests this week, according to officials.
The steam generator tubes are located inside the plant's Unit 3 reactor. The reactor was shut down late January after a leak was found.
"It's kind of frightening when they're failing, especially living in a beach community this close to San Onofre," said San Clemente resident Tom Eikmeier.
Small traces of radioactive gas escaped during the leak in January, but officials with Southern California Edison (SCE), the company that runs the plant, said there was no danger to workers or residents.
Unit 3 testing has taken place since then. Officials said that out of nearly 20,000 tubes, 129 showed premature wear and are being tested. The tests involve pumping water inside a tube at a high pressure.
The Nuclear Regulatory Commission is trying to figure out why the tubes are wearing out so quickly in a system that's only two years old.
In a statement, the NRC said: "The integrity of steam generator tubes is important because the tubes provide an additional barrier inside the containment building to prevent a radioactive steam release. Steam generators do experience some wear during the first year of operation but the level of tube wear at Unit 3 is unusual."
Investigators have been looking into excessive wear on tubes in Unit 3 and its twin, Unit 2, which has been offline for maintenance.
"We have lived in San Clemente for the last 15 years and never felt comfortable about having the power plant next to us, because we know what happened in Japan," said San Clemente resident Monica Lussi.
Other residents say it's not something that they worry about.
"I think what's going to happen is what's going to happen," said San Clemente resident Tanner Payan.
In a past statement, SCE officials said Unit 3 wouldn't return to service until they're satisfied it's safe to do so. A Nuclear Regulatory Commission inspection team is expected to start work at San Onofre on Monday.